In a photographic printer in which a strip of photographic paper is used, the photographic paper which has been exposed is rolled up in a roll-up magazine. In order to roll up the photographic paper in the roll-up magazine, a roll-up shaft is provided inside the magazine, and the photographic paper is rolled round the roll-up shaft. In order to roll the strip of photographic paper round the roll-up shaft, a slot could be provided in the roll-up shaft. The end of the photographic paper is inserted into the slot in the shaft and fixed, and then the paper is rolled up by rotating the roll-up shaft. However, such an operation is apt to be a daylight operation when it is conducted manually, and even when it is conducted as a dark-room operation, a waste of time and photographic materials can not be avoided. When the end of the photographic paper is inserted into the slot of the roll-up shaft, in particular, a fold is made in the end and this part can not be used. Therefore, it has been common practice to roll the photographic paper firmly round the roll-up shaft several times and then roll up the paper later by using the frictional force thereof. In this case, however, it is necessary to confirm the secure rolling of the photographic paper round the roll-up shaft. Many attempts have been made to automate the rolling-up of the printing paper, as described in Japanese Patent Laid-Open No. 124,725/79, from which no satisfactory results have so far been obtained.